I went the other way around. So maybe no help. But here's my input. DL is the original deal and no matter what I think everyone that loves Disney should do it at least once.
DL in general will cost more or about the same as you'd spend for something longer at WDW. But at DLR you will accomplish much more in 3 days than you would at WDW in 5 days. DLR is also much easier on the feet. The distances walked are significantly reduced. Don't get me wrong, you still want comfortable shoes.
Rides, some you'll like better at DLR some are better at WDW.
WOC at DCA is by far the best night time show of all time at Disney. A definite must do.
Food is not a big deal at DLR and ADRs don't exist. Priority Seating 60 days out no fees for no shows. Blue Bayou for ambiance not the food. But still a must do one time if you ask me.